Johnston fought off stiff competition from Louisa Ellis and Steven Lickley in the final episode to show the judges how far he could push himself.

Challenges in the competition included creating and delivering a Michelin-standard dish for 23 gastronomical giants from around the world, travelling to the south of France to learn in two Michelin-starred kitchens of the fourth best restaurant in the world – Mirazur from Argentinian chef Mauro Colegreco.

The ultimate challenge for the final three chefs was to create the best three-course meal of their lives for judges Marcus Wareing, Monica Galetti and Gregg Wallace in three hours.

Judge's praise

Judge Marcus Wareing added: “You don’t come across cooks like this very often. We’ve just found a star of the future. What a fabulous talent – 21 years old, amazing.”

Fellow judge Monica Galetti added: “Not only is he good in the savoury section, but he has produced some out-of-this-world desserts as well.”

Judge Gregg Wallace said: “The best chefs in the world learn and create their own style, and that is what I have watched Johnston do in this competition – dish, after dish, after dish.”

Johnston trained at a two-AA rosette restaurant Boulters in Maidenhead, Berkshire, after he finished school under chef Daniel Woodhouse. While working there he achieved NVQ levels 2 and 3 in professional cookery from Henley College.

Johnston outlined his future plans, which included heading more towards fine dining and continuing to learn.

He said: “As the next step in my career, I would love to focus more on fine dining and push myself to learn more while I can.

“My ambitions, longer term, are to learn as much as I can still while I am young, and hopefully when the time is right, in years to come, step up to my own head chef role.”